JPS59217258A - Magnetic recording and reproduction system - Google Patents

Abstract

PURPOSE:To detect a tracking error and to perform excellent tracking control by utilizing two pilot signals which differ in frequency, and the azimuth angle of a recording and reproducing head. CONSTITUTION:An analog signal is inputted as a recording signal to an input terminal 1 and converted into a digital signal by an A/D converter 3. A drum pulse, on the other hand, is inputted to an input terminal 2. The output of a recording amplifier 8 is connected to a head HA or HB constituting the recording and reproducing head HR through a switch 9 to perform recording. In this case, the signal is recorded on every two tracks at a different carrier frequency while the azimuth angle is different between adjacent tracks, and FM signals different in carrier wave frequency are reproduced from tracks on both sides of a track being reproduced and separated to detect a tracking error from their relative level difference. Namely, the FM signals themselves are utilized as pilot signals in this case, so optimum tracking control is performed easily without any control track onto a tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a magnetic recording and reproducing system in which recording tracks and tracks are arranged in parallel in the width direction, and particularly to track and king control thereof.

[Technical background of the invention]

In a magnetic recording/reproducing device in which recording tracks are arranged in parallel in the width direction, such as a rotating magnetic head type VTR (video tape recorder), a control signal synchronized with the rotation of the rotating magnetic head is generally sent during recording. The tape is recorded on a control track, and during playback, the tape transport speed is varied using a cab stan motor etc. according to the phase shift of the control signal. is in control.

According to this method, it is necessary to specially provide a control track for tracking control on the magnetic tape. Furthermore, since the distance from the point where the rotating drum and tape begin to contact to the control signal control to the do (fixed head) is long (this distance varies depending on the system, for example, for consumer A-inch cassette video (In a recorder, the distance is about 70 to 80 vans.) Therefore, it is not possible to accurately detect the tracking error at the position of the rotating magnetic head. Tracking errors are likely to occur due to expansion and contraction of the tape due to changes in the tab and tape tension, uneven rotation of the capstan motor, etc., so extremely accurate tape tension and motor speed control are required.

Furthermore, although it is desirable that the recording track be recorded in a straight line on the tape, in reality it is recorded in a slightly curved shape on the magnetic tape due to the instability of the tape running system determined by mechanical precision. It is normal to Furthermore, in recent years, the density of magnetic recording and reproducing has been promoted, and track widths are becoming narrower. In addition, magnetic recording and reproducing devices with narrow tape widths (such as so-called "8 mm video") are also being considered.
On the other hand, tape thickness is becoming thinner and thinner.
More precise tracking control has become necessary.

Therefore, a pilot signal different from the main information signal is recorded on the recording track, a racking error is detected using the pilot signal without using a control signal, and a capstan motor etc. is used to rotate the head in the longitudinal direction of the tape. Various methods are being proposed in which tracking control is performed by moving the scanning locus of the head and displacing the rotary head in the width direction of the recording track using a topping mechanism.

For example, as shown in Figure 1, three types of pyrotechnical signals f*-/s of different frequencies are recorded superimposed on the main information signal, and when playing back, three adjacent tracks are simultaneously played back. The main information signal is obtained from the center track among the two tracks, and the main information signal is obtained from the tracks on both sides. A method has been considered in which pilot signals are obtained, these pilot signals are compared with each other, and tracking control is performed based on this comparison signal.

In FIG. 1, when the do H is at the position PJ shown in the diagram, the armpit signal f1 is detected from the adjacent track on the left side of the diagram, the mother pilot signal /S is detected from the track on the right side of the diagram, and the relative relationship between these two signals is detected. The direction of tracking deviation and 1 are determined from the level difference. Similarly, Hera r
When the head H is at the position P2 in the figure, the pilot signal f2 is detected from the left track, and the /mother pilot signal f1 is detected from the right track, and when the head H is at the position P3 in the figure, the pilot signal f3 is detected from the left track.
Tracking control is performed by detecting pilot signals f2 from the right track.

According to such a system, the number of oscillators corresponding to the number of types of pilot signals is required, and a filter for separating and extracting the four pilot signals is also required. If there are a large number of control signals, the circuit configuration will be complicated, and the switching operations thereof will also be complicated. Therefore, it is preferable that the number of pilot signals is small.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording and reproducing method that allows tracking errors to be detected in a simple manner and to perform good tracking control without providing a control track.

[Summary of the invention]

The present invention performs tracking control using pilot signals of two frequencies and azimuth angles for recording and playback. During recording, two types of signals with different frequencies are sent to each track alternately. , and the azimuth angles are made different between adjacent tracks, recording is performed with two types of azimuth angles, and during playback, the 2' signals with different frequencies are reproduced from the track being played back, the adjacent track on both sides of the track, and the track track being played back. It is characterized in that tracking control is performed by detecting tracking deviation from the relative level relationship.

[Embodiments of the invention]

Several embodiments will be described in which the present invention is applied to a rotary head type PCM ZF pulse code modulation type tape recorder.

FIG. 2(a) shows the rotating head W in these embodiments.
The winding of the data T around the PCM0M chip recorder rotary drum RD shows the state of the winding, and FIG. That is, in these embodiments, as shown in FIG. 2(a), the data T is wound around the rotating drum RD by slightly more than 180 degrees and the data T is caused to travel, and recording or reproduction is performed by one tora per one rotation of the drum RD. And also,
As shown in Figure (b), the recording/reproducing direction HRP has a positive azimuth angle set at a distance TH, and a gap l'f (A and an azimuth angle of 1 minus) forming a dog gap fGk. To hold, to form a do gap GB, to do H
It is a composite Ajibus head configured by integrating B.
The width is TW1 both gears, and the f interval is TH. The rotating drum still rotates at a constant speed both during recording and playback.

FIG. 3 shows the configuration of the recording side of the first embodiment of the present invention.

In Fig. 3, 1 is the input terminal for the recording signal, 2 is the input terminal for the drum/arm which is synchronized with the rotation of the rotating drum, 3 is the Φ converter that converts the recording signal into digital (M number), and 4 is the digital modulation terminal. The circuits 5 and 6 are first circuits that modulate the output of the digital modulation circuit 4 using FM (frequency modulation method).
and a second FM modulation circuit, 7 is a first FM modulation circuit. A switch for selectively deriving the output of the second FM modulation circuits 5 and 6 according to the output of a second frequency divider 12, which will be described later; 8 is a recording amplifier; 9 is a first frequency divider, which will be described later. 10 is a drum frig f() which divides the frequency of the drum/4' pulse and shapes the waveform.
Hereinafter [referred to as drum F/F j]. 1st note is drum F/
A first frequency divider 11i'10 divides the output by A, and 12 is a second frequency divider that divides the output of the first divider J1.

The operation of FIG. 3 configured as described above will be explained in detail with reference to the timing chart shown in FIG. 4. An analog signal such as a music signal is input as a recording signal to the input terminal 1 and is converted into a digital signal by the digital converter 3. On the other hand, the input terminal 2 is shown in Fig. 4(a).
A drum/4' pulse waveform as shown in is input. The drum pulse is 180″ on the same circumference as the rotating drum RP.
It is detected by two magnets (not shown) attached at different positions and a fixed detection head (not shown), and is a positive/negative signal synchronized with the rotation of the drum. The drum/4' pulse shown in FIG. 4(a) is converted by the drum F/F 10 into a nocelus having a waveform as shown in FIG. 4(b).

That is, the drum F/F No. 0 operates so as to be set by a positive drum pulse and reset by a negative drum pulse. Therefore, the output of the drum F/'F 10 shown in FIG. 4(b) is a pulse synchronized with the rotation of the drum, and the period of ---irrepel or low level corresponds to strong rotation of the drum RD. The output of the drum F/F 10 is input to the first frequency divider 1, and the frequency is divided by A to the fourth frequency divider.
A noyalus with a waveform as shown in Figure (C) is output. Furthermore, the output of the 10th frequency divider 1 is inputted to the 10th frequency divider 1, where it is frequency-divided by W to create a waveform as shown in FIG. 4(d).
and rus are output. The output of the ψ converter 3 described above is input to a digital modulation circuit 4. The output of the drum φ10 (FIG. 4(b)) is also input to the digital modulation circuit 4. The digital modulation circuit 4 digitally modulates the digitally converted recording signal using a modulation method such as the so-called pi-phase method, and further compresses this digitally modulated signal in the time axis direction at a ratio of 100% to the drum F/F. The compressed data is output only during the period when the output of No. 10 is in contact with the fT, that is, to the recording/reproducing device composed of the composite azimuth head. The output of the digital modulation circuit 4 is transmitted to the first FM modulation circuit 5.
and the second FM modulation circuit 6 respectively.
Modulated. Carrier frequency f of the first FM modulation circuit 5
The carrier frequencies f of the first and second FM modulation circuits 6 are set to values that enable separation of two FM signals based on these by a BPF (pantone filter) during reproduction, which will be described later. The outputs of the first FM modulation circuit 5 and the second FM modulation circuit 6 are connected to a terminal a and a terminal of a switch 7, respectively. The switch 7 selectively switches and derives the outputs of the first and second FM modulation circuits 5 and 6 according to the output of the second divider 12 (FIG. 4(d)), and The output signal of the 20th frequency divider 12 is switched to the a side of the period switch 7, and the low level intercostal signal is switched to the b side. In other words, the switch 7 is switched every two rotations of the drum.
Recording is performed by being connected to the head HA or head HB constituting the RP. The switch 9 is switched to the terminal C side when the output of the first frequency divider 11 is at a high level, and to the terminal d side when the output is at a low level.

That is, the head HA and head HB are switched each time the drum rotates once. Further, during recording, the tape T is always running at a constant speed, but the running speed is set so that recording is performed while overlapping adjacent tracks. This situation is shown in FIG. 5(a).

First, a track TA having a width Tw is recorded by the positive azimuth head HA at the nth rotation of the drum RD. Next, the track TB is recorded by the minus azimuth head HB at the n+1 rotation of the drum RD, but the head fT is traveling by T in the track width direction for 7 minutes so that the tracks TA and T overlap. , head HB
scans partially overlapping track TA, so the overlapping portion of track TA is erased and becomes track TI.

In this way, recording tracks are formed on the tape T, as shown in FIG. 5(b), with track widths Tw' and tracks that match hv and have different azimuth angles. In this case, the head HA and head HB" shown in FIG. 2(b)
The deviation between the tracks TA and TH due to the interval TH can be ignored in many cases because TH is sufficiently small compared to the track length.

Furthermore, as described above, since the first FM modulator 5 and the second FM modulator 6 in FIG. 3 are switched every two rotations of the drum, the carrier frequency of the recorded signal differs for every two recording tracks. value. This situation is shown in FIG. 5(c).

The principle of tracking control when reproducing a tape recorded in this manner will be explained using FIG. 5(c).

First, a recording/reproducing head HR consisting of a composite head
Consider the case where P scans track M. Since the azimuth angle of track TA is different from that of tracks TB0 and HI11, the playback output of head HA is different from that of track TA.
At the signal of , truck TII. Oyohi Truck TB
, the signal is not reproduced. The reproduction output of head HB is the signals of tracks T, 10 and Tl, and the signal of track M is not reproduced. And truck TB
The FM signal frequencies of 0, Tora, and Tl are f and fl, respectively, and are different. Therefore truck TB
Information on tracking deviation can be obtained by using the FM numbers of o and TB as pilot signals. That is, information on tracking deviation can be obtained by separating the components of two FM numbers, ie, pilot signal frequencies f, and t2 from the reproduced output of the head HB and comparing their levels with each other. In this case, if the recording/reproducing head HRP is shifted to the left side of the track TA, then the head HB is
The area facing (contacting) track TBo increases, and the area facing track TB decreases, so fz acid component f
The 11th minute is also a big deal, and on the other hand, if the HRP is shifted from track M1 to the right side in the diagram, then the f11 minute is f.
.

The ingredients are also large. More f! The absolute value of the relative level difference between the component and f22 represents the tracking deviation amount of the tiger, riTA, or rat. In this way, RAD H to record and playback
When the RP scans the track T, the reproduction output of the head HA obtains a signal of TRA, RITA, and then goes to HB.
Reproducing output power C) ) 5 Tracking control is performed by obtaining the y-king deviation direction, the kink deviation amount, and the king error signal. Similarly, when the HRP sequentially scans tracks TB1, TA2, TlI2, etc., the signals of each track are sent to the head HB,
The tracking error signal is reproduced by head HA and head f (B...), and the tracking error signal is reproduced by head 9HA and head HB
, the reproduction output power of the head HA<... is obtained. Then, the tiger and king error signals are 71, f from the head reproduction output.
* Obtained by separating the acid component and comparing these levels with each other. If we now use Cfx - fl ) as the tracking error signal, the polarity of the tracking error signal represents the tracking deviation direction, and the absolute value force; tracking deviation represents quantity. At this time, the polarity of the tracking error signal differs depending on which track, left or right, the pilot signals /l and I2 are obtained from in terms of the tracks being scanned.

Taking FIG. 5(C) as an example, when the head scans the track Tm1 and when the head scans the track TB, the tracking error signal will change even if tracking deviation occurs in the same direction. Polarity is different. Such reversal of the polarity of the tracking error signal occurs when moving from track TAn to track TlIn, that is, every two recording tracks, so if the polarity of the tracking error signal is reversed at this timing, the tracking error can be reduced. The polarity of the signal can always be made to correspond to tracking deviation in the same direction.

FIG. 6 shows the configuration of the reproduction side of this first embodiment. In FIG. 6, parts that are the same as those on the recording side (FIG. 3) (that is, parts that are also used) are designated by the same reference numerals as in FIG. 3.

In Fig. 6, 2 is an input terminal for drum pulses synchronized with the rotation of the rotating drum, 10 is a drum F/F that divides the drum frequency by 1000s and shapes the waveform, and 11 is a drum F/F.
The 10th frequency divider divides the output of /F J O by A, 12 is the 20th frequency divider υ that divides the output of the first frequency divider 1, and the above is the same as in Figure 3. are the same. 20 is a third frequency divider which divides the output of the first frequency divider 1 by A so that its output phase is different from the output of the tenth frequency divider 12 by 90 degrees.
2 is a frequency divider, 2 is a first reproduction amplifier that amplifies the reproduction output of the head HA, 22 is a second reproduction amplifier that amplifies the reproduction output of the head HB, 23 is a first reproduction amplifier. The first switching circuits 24 and 25 switch which of the outputs of the second reproduction amplifiers 21 and 22 is used for tracking control according to the output of the 10th frequency divider 1, respectively. The first and second four-thousand filters (r B
It is called PF J. ), 26 and 27 are the first
and first and second level detection circuits that detect the levels of the outputs of the second BPFs 24 and 25;
and a second switch for switching whether the outputs of the second level detection circuits 26 and 27 are connected to the inverting input terminal or the non-inverting input terminal of the differential amplifier 29 according to the output of the third frequency divider 20. circuit, 29 is a pilot signal f*, f
A differential amplifier for determining the relative level difference of z, 30 is a tiger,
Output terminals for the King error signal; 3 and 32 are first and second FM demodulation circuits that demodulate signals FM modulated at carrier signal frequencies f1 and f:, respectively; 33 is the output of the 20th frequency divider 1; 34 is a digital demodulation circuit that digitally demodulates the signal derived by the switch 33; 35 is the output of the digital demodulation circuit 34; 36 is a reproduction signal output terminal. Also, P.G.
is a timing error generation system, TE is a tracking error detection system, and MP is a main information signal reproduction system.

Next, referring again to the timing chart of FIG. 4, the operation of FIG. 6 will be explained in detail.

A drum pulse as shown in FIG. 4 (II) is input to the input terminal 2. The drum pulse is a positive or negative 1,000 rus synchronized with the rotation of the drum, similar to that used during recording. And drum F/F i o, 10th frequency divider 1, 2nd frequency divider 1
2 to 4 (b) and (e).

Waveforms as shown in (d) are output.

Everything up to this point is exactly the same as when recording. 30th frequency divider 20
substantially similar to the second frequency divider 12, divides the output of the 10th frequency divider 11 by A and outputs it, but the phase of the output of the 30th frequency divider 20 is the same as the waveform shown in FIG. 4(e). The second frequency divider No. 2
The phase of the output (FIG. 4(d)) is shifted by 90° (corresponding to 180°=half cycle of the output of the first branching unit 11). Furthermore, the reproduction outputs of the heads HA and HB are input to the first switching circuit 23 after being amplified by the first and second reproduction amplifiers 2 and 22, respectively. 1st. The amplification factors of the second reproduction amplifier 7'27°22 are set to be equal. The first switching circuit 23 inputs the outputs of the first and second reproduction amplifiers f21 and 22 to the first and second BPFs 24 and 25, respectively, according to the output of the first frequency divider 1. It is selectively switched whether the signal is input to the first or second FM demodulation circuits 3 and 32. That is,
The first switching circuit 23 is for switching which of the reproduced outputs of the heads HA, HA, and HB is used as tracking information, and is connected to the first frequency divider 11 as shown in FIG. 4(c). During the period when the output of the first reproduction amplifier 2 is at a high level, the output of the first reproduction amplifier 2 is at the high level. It is connected to the input of the second FM demodulation circuit 31.32, and the output of the second reproduction amplifier 22 is connected to the input of the first FM demodulation circuit 31.
It is connected to the input of the second BPF 24 , 25 . Conversely, during the period when the output of the first frequency divider 1 is at a low level, the output of the first reproducing amplifier 2 is at a low level. Second BPF 24,2
5, and the output of the second playback amplifier 7'22 is connected to the input of the first. It is connected to the input of the second FM demodulation circuit 31,32. The first and second FM demodulation circuits 3 and 32 demodulate the FM signals modulated as carrier frequencies fl and f2, respectively, and their outputs are connected to terminals e and f of the switch 33, respectively. . The switch 33 switches between the first and second frequency dividers according to the output of the second frequency divider 12 (FIG. 4(d)). The outputs of the second FM demodulation circuits 31 and 32 are selectively switched and derived. That is, during a period when the output of the second branching unit 12 is at a high level as shown in FIG. 4(d), the switch 33 is switched to eflQ, and during a period when the output is at a low level, the switch 33 is switched to the t side. Rima Citruk 2
The first FM demodulation circuit 3 and the second FM iJ modulation circuit 32 are switched for each record. The signal derived by the switch 33 is the output of the drum F/F 10 (Fig. 4(b)
)) is input to the digital demodulation circuit 34. Since this signal is compressed in the time axis direction at a proportional ratio during recording, the digital demodulation circuit 34 restores the signal to its original time relationship, and further digitally demodulates it and outputs it. D/A
The converter 35 converts the output of the digital demodulation circuit 34 from a digital signal to an analog signal, and outputs the analog signal to an output terminal 36 as a reproduced signal. On the other hand, the first and second BP
F24 and F25 have their passband centers set at the FM signal group wave numbers f and f3, respectively, and fl and f! from the head reproduction output. Separate the acid components so that they can be used as signals. The outputs of the first and second BPFs 24 and 25 are
The levels are detected by level detection circuits 26 and 27, respectively, and voltages corresponding to the respective levels are inputted to the inverting input terminal and the non-inverting input terminal of the differential amplifier 29 via the second switching circuit 28, respectively. The second switching circuit 28 connects each output of the first and second level detection circuits 26 and 27 to the inverting input of the differential amplifier 29 in accordance with the output of the third frequency divider 20 (FIG. 4(e)). , selectively switches which of the non-inverting input terminals is input. That is, as described above, the second switching circuit 28 inverts the polarity of the tracking error signal every two recording tracks so that the polarity of the tracking error signal always corresponds to tracking deviation in the same direction. The output of the frequency divider 2o of 3 (Fig. 4 (e)
) ) Kahairehel period line first level detection circuit 2
6 is input to the inverting input terminal, and the output of the second level detection circuit 27 is input to the non-inverting input terminal, and conversely, during the low level period, the output of the first level detecting circuit 26 is input to the non-inverting input terminal, Switching is performed so that the outputs of the two level detection circuits 27 are respectively input to the inverting input terminals. The differential amplifier 29 amplifies the level difference between the two input signals, that is, the /1 and f10 level difference. The output of the differential amplifier 29 is then outputted to a terminal 30 as a tracking error signal. This tracking error signal is 0 if tracking is performed correctly; if it deviates to the right, it becomes a positive polarity voltage; if it deviates to the left, it becomes a negative polarity voltage; its absolute value is the tracking deviation. represents quantity. therefore,
The tracking error signal is used to control either or both of a tape feeding mechanism such as a capstan motor (not shown) and a head moving mechanism using a piezoelectric bimorph, etc., so that the best tracking can be achieved at all times. You can get the status.

As described above, according to the first embodiment, recording is performed by changing the FM carrier frequency for every two tracks, and by making the azimuth angle different for adjacent tracks. FM signals with different signal frequencies, that is, in this case, the FM signal itself is
Since these signals are used as the front and back signals, it is possible to easily perform the best tracking control without providing a control track on the tape.

In addition, in the first embodiment, the carrier signal frequency of the FMi number to be recorded is alternately switched every two tracks.
Although the 4 pilot signal is used as a pilot signal, a tracking error may be detected by recording a pilot signal having a frequency provided separately from the FM carrier signal frequency and superimposing it on the main information signal.

Furthermore, the main information signal may be directly recorded without FM modulation, and a pilot signal may be superimposed thereon and recorded. This is a second embodiment of the present invention, and FIG. 7 shows the structure of the recording side, and FIG. 8 shows the structure of the reproducing side.

In addition, in these FIGS. 7 and 8, the first
In this embodiment, parts having the same functions as those in FIGS. 3 and 6 are designated by the same reference numerals, and FIGS.
Parts that use common inspection in the figures are indicated by the same reference numerals.

Differences between the second embodiment and the first embodiment will be explained. In FIG. The oscillator 42 is a switch that selectively switches and derives the outputs of the first and second oscillators 40 and 4 according to the output of the 20th frequency divider 12. In the first embodiment, two FM modulation circuits 5 and 6 having different carrier signal frequencies are prepared.1. The way of output is changed according to the output of the second branching unit 12 (FIG. 4(d)), but in the second embodiment shown in FIG. are prepared, and their output is switched in accordance with the output of the second frequency divider J2 and superimposed on the main information signal. Further, the main information signal is directly recorded without FM modulation.

In this way, a recording pattern similar to that of the first embodiment as shown in FIG. 5(c) is obtained, and during reproduction, the pilot signal is separated and extracted and used for tracking control.

In FIG. 8, TE as in the case of FIG.

MP and PG are a tracking error detection system, a main information signal reproduction line, and a timing error generation system, respectively. The tracking error detection system TE is completely similar to the first embodiment shown in FIG. The main information signal reproduction thread MP differs from the first embodiment in that the main information signal is not FM modulated.
No need to demodulate. Therefore, it is not necessary to output a signal for switching the output of the FM demodulation circuit as in the first embodiment for the timing signal and the lusus generating thread PG.

Thus, according to the second embodiment, the frequency! ! , f
The pilot signals of s are used alternately for every two tracks, and are recorded with different azimuth angles for adjacent tracks together with the main information signal. During playback, two pilot signals are used for the tracks on both sides of the track being played. Since the data is reproduced using a head with the same azimuth as that used for recording and separated, and the tracking error is detected from the relative level difference, the best tracking control can be performed without providing a control track on the tape.

In the first and second embodiments, an example was shown in which the pilot signal is continuously recorded on the track together with the main information, but the pilot signal may be intermittently recorded on a predetermined portion on the track. , you may use this. A third embodiment of the present invention in which the 1,000-lot signal is intermittently recorded as described above will be described.

In this third embodiment, as in the second embodiment, the main information signal is directly recorded without FM modulation.

Figure 9 shows the recording side, and Figure 12 shows the playback side.

Figures are shown for each. The first embodiment shown in FIGS. 3 and 6 has the same or similar functions as the second embodiment shown in FIGS. 7 and 8. , and are shown with the same reference numerals as in FIGS. 7 and 8.

The timing chart in FIG. 10 shows the recording operation in FIG. 9 (particularly in FIGS. 10(a) to (d) and
This will be explained with reference to f)).

A drum signal as shown in FIG. 10(,) is input to the input terminal 2, and the drum F/F J o outputs a signal as shown in FIG. 10(b). This frequency is divided into μ by the first frequency divider 1 as shown in FIG. The frequency is divided by A and a mother pulse as shown in FIG. 10(d) is output. In addition, a recording signal is input to input terminal 1, and A
/D converter 3 converts it into a digital signal. The above is exactly the same as in the first and second embodiments.

The armpit generator 50 has a drum recorder. The pulse generator 5o receives the output of the drum F/F 10 (see FIG. 10(b)) as shown in FIG. 10(f).
) generates and outputs N pulses during the irregular period. The digital modulation circuit 4 includes the output of the converter 3, the output of the drum b10, and the pulse generator 5.
An output of 0 is input respectively. Digital modulation circuit 4
After digitally altering the recorded signal, that is, the main information signal, which is converted into a digital signal, the data corresponding to the time of one rotation of the drum is outputted from the drum F/F 10 (Fig. 10(b)).
) is compressed in the time axis direction until the time corresponding to the period when the output of the drum F/F 10 is high level and the output of the pulse generator 50 is at a low level. The output power of the generator 50 is output during the O-level period. The output of the digital modulation circuit 4 is connected to the terminal g of the switch 5.

On the other hand, the first oscillator 40 and the second oscillator 41 each output signals of fl and one overlapping frequency.
These outputs are connected to the terminal of the switch 5 via a switch 42 which is switched according to the output of the second branch 12.

That is, the period when the output of the second frequency divider No. 2 shown in FIG. 10(d) is at a high level is fl, and the period when it is at a low level is f3.
are respectively led out to the terminals of switch 5. The signals of frequencies fr and f* are respectively used as mother pilot signals during reproduction. Switch 5 is the pulse generator 5
The output of the digital modulation circuit 4 and the pilot signal f1 or fl are selectively switched and derived according to the output of the digital modulation circuit 4 (FIG. 10(f)), and input to the recording amplifier 8.

The switch 5 is switched to the g side during the period when the output of the pulse generator 50 is at a low level, and is switched to the h0 (If) side during the period when the output of the pulse generator 50 is at a high level. In the same way as in the embodiment and the second embodiment, the output of the tenth frequency divider 10 (FIG. 10(C)
) via the switch 9 which is switched according to the head HA.
Alternatively, it is connected to the head HB and recording is performed.

The recorded tracks recorded in this way are recorded at N predetermined portions for each track (during the period corresponding to the high level of the output of the system generator 50 as shown in FIG. 10(f)). iro, ) signal is recorded. Furthermore, the frequencies of the main plot signals differ for every two tracks, and the azimuth angles differ between adjacent tracks.

FIG. 11 (&) is an enlarged view of the portion where the pyro and g signals are recorded. TA1 shown in FIG. 11(a)
and TA2 ('rl, and 'rB2) are lengths 2 determined by the relative inclination of the tape and rotating drum and the track width.
It is shifted by TH' in the length direction of the track. Therefore, the sections T in which the noquilot signals of TA and TA2 (T"1 and Ta2) are recorded are also shifted by 2 TH'. Also, as shown in FIG. 2(b), the head H
Since A and head HB are TP [#, TA, and TB
, are shifted by (TH'Ta), and TB, TA2 are shifted by (TIE' + TH).

i4 from both tracks while playing a certain track.
The section where the Iro and G signals can be played at the same time is '(
T, -2TH/), and considering that the head HA and head HB are separated by TII, then,
When reproducing a pilot signal on head HB while the main information signal is being reproduced on head HA, and when reproducing a pilot signal on head HB while reproducing the main information signal on head HB, this is common to both cases. The period in which the original signal can be reproduced from the tracks on both sides is substantially shorter, p (T, −
2TR'-2TH). The pulse width of the output of the above-mentioned pulse generator 50 is determined so that (T, -2TH' 2Tu ) is positive, as shown in FIG. 11(b). During the high level period of the virtual waveform as shown in FIG. 11(e), it is also possible to use the head HB to reproduce the arm pilot signal while the main information signal is being reproduced by the head HA. It is also possible to reproduce the mother pilot signal using the head HA while the main information signal is being reproduced.

Next, the operation on the playback side shown in FIG. 12 will be explained with reference to the timing chart of FIG. 10 (particularly FIGS. 10(a) to 10(C) and FIGS. 10(-) to 10(b)).

A drum pulse as shown in FIG. 10(a) is input to the input terminal 2, and the drum F/F 10 outputs a signal as shown in FIG. 10(b). 10th frequency divider 11 Hageram y, lr J
The third frequency divider 20 divides the output of the first frequency divider 1 by A and outputs the signal shown in FIG. 10(C).
The frequency is divided and the signal shown in FIG. 10 (,) is output. /4'
As shown in FIG. 10(f), the pulse generator 50 generates and outputs N pulses during a period when the output of the drum F/F 10 is at the low level. The output of the pulse generator 50 and the output of the tenth frequency divider 11 are input to the timing signal generation circuit 55 . Timing signal generation circuit 55
is the timing pulse AT as shown in Figure 10 (2))
A timing pulse BT as shown in FIG. 2(h) is output. Timing/Solus AT converts the output of the pulse generator 50 (FIG. 10(f)) to the output of the first frequency divider 1 (
The timing chart BT is based on the rise of the output of the arm pulse generator 50 as shown in FIG.
This is a narrow /4' pulse generated during the high level period of the virtual waveform as shown in c). The playback outputs of HA and HB are amplified by the first and second playback amplifiers 2 and 22, respectively, and then sent to the terminal i of the switch 52.
1 is supplied to terminal j. The switch 52 is switched according to the state of the timing/4' pulse AT (FIG. 10(g)) described above, and the switch 52 is switched between the first and second reproduction amplifiers 2 and 22.
Selectively derive the output of . That is, the switch 52 is switched to the i side during a period when the timing chart AT is at a high level to derive the output of the first reproduction amplifier 2 and the reproduction output from the tamashi head HA, and is switched to the j side during a period when the timing chart AT is at a low level. Then, the output of the second reproduction amplifier 22 and the reproduction output of the IT head HB are derived. The signal derived by the switch 52 is sent to the digital demodulation circuit 34 and the first BPF.
24 and second BPF 25, respectively. The output of the drum unit 10 and the output of the pulse generator 50 are also input to the digital demodulation circuit 34 . Of the head reproduction outputs input to the digital demodulation circuit 34, the main information signal is the one during the period when the output of the drum F/F 7o is at a low level and the output of the armpit generator 50 is at a low level. Since the main information signal is compressed in the time axis direction during recording, the digital demodulation circuit restores the time relationship of the main information signal to its original state, and further digitally demodulates and outputs the signal. The output of the digital demodulation circuit 34 is converted into an analog signal by a D/A converter 35 and outputted to an output terminal 36 as a reproduced signal. On the other hand, the centers of the passbands of the first and second BPFs 24 and 25 are set to the frequencies of the motherboard signals fl and f2, respectively.
1 and fs are separately extracted. However, as mentioned above, the pilot signal is recorded within N times per tiger, so the first... 2nd BPF 24, 25
No. 1 can be detected only when the head is switched by the switch 52 to detect the pilot signal, that is, only during the period when the armpit generator output is at No. 1 as shown in Fig. 10(f). The outputs of the first and second BPFs 24 and 25 are input to the first and second level detection circuits 26 and 27, respectively, and the frost 1 pressure corresponding to each level is output.
The outputs of the 20th level detection circuits 26 and 27 are respectively connected to the first and second Zannor and hold circuits (
(hereinafter referred to as "r878 circuit") 53 and 54. The timing pulse BT is also input to the first and second S/H circuits 53 and 54, and the outputs of the first and second level detection circuits 26 and 27 are the rising edge of the timing pulse BT. It is sampled at the timing of υ and its value is held and output.

As mentioned above, even if the reproducing head is head HA, the rising timing of timing pulse BT is different from head HB.
However, the reproduction output is determined to reliably become a pilot signal.

The outputs of the first and second S/H circuits 53 and 54 are inputted to an inverting input terminal and a non-inverting input terminal of a differential amplifier 29 via a second switching circuit 28. The second switching circuit 28 switches between the first and second switching circuits according to the output of the 30th frequency divider 20 (FIG. 10(e)). The polarity of the tracking error signal is inverted every two tracks by selectively switching whether the output of the circuits 53 and 54 is input to the inverting input or the non-inverting input of the differential amplifier 29. The polarity of the tracking error signal always corresponds to the tracking deviation in the same direction, which is the same as in the first and second embodiments. The level difference between the two signals, that is, the pilot signal fs and f20
The level difference is amplified and output as a tracking error signal to the output terminal 3o. Using this tracking error signal, in the same way as in the first and second embodiments, both the gear moving mechanism using a capstan motor (not shown) and a piezoelectric element bimorph etc. Tracking control can be performed by controlling either one of them.

In this third embodiment, during recording, the pilot signals f1 and f are intermittently sent to each track, and fx, f
s is recorded alternately on every two tracks, and during playback, the 4-lot signals of each track on both sides of the track being played are recorded on different azimuths from the track being played.
・mother signal f1・/
Since the tracking error is detected from the relative level difference between , tracking and kinging control can be performed without providing a control track on the tape. In this embodiment, the pilot signal is intermittently recorded N times per recording track, but the number of times the pilot signal is recorded is arbitrary. For example, a pilot signal may be recorded only once per recording track, and tracking control may be performed using only the tape feeding mechanism.

Furthermore, in the first to third examples, the winding of the tape on the drum may be completely arbitrarily set as to the number of corners, compound edges, and number of dots.

Furthermore, in the first to third embodiments, the main information signal is P
Although it is assumed that the main information signal is converted into a commercial and further compressed in the time axis direction, the format of the main information signal is also arbitrary. For example, various methods have been devised for improving the image quality when playing back still images, etc. using a composite azimuth head in a consumer row inch cassette type VTR, and in the case of a VTR using such a composite azimuth head For example, if a pilot signal is recorded during the vertical retrace period or horizontal retrace period of the video signal and the tracking error is detected, tracking control can be performed without using a control signal.

It goes without saying that the present invention can be implemented with various modifications without departing from the gist thereof.

〔Effect of the invention〕

In the present invention, two signals with different frequencies are recorded alternately every two tracks and with different azimuth angles on adjacent tracks. It is possible to provide a magnetic recording and reproducing system that reproduces two signals and detects a tracking error from the relative level difference between them, thereby achieving the best tracking control without providing a control track on the tape. can.

Moreover, according to the present invention, since there are two types of signals to be used as pilot signals, signal processing and circuit configuration can be simplified. Furthermore, since the present invention uses the frequency information of the pilot signal and does not use the phase information, recording is easy, and furthermore, the head for reproducing the signal used as the base pilot signal is used during recording. Another advantage is that it can be used for multiple purposes.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining an example of the prior art of the tracking control system, and FIGS. 2(a) and (b) show the configuration of the tape and rotating head portions and the composite azimuth head in each embodiment of the present invention, respectively. FIG. 3 and FIG. 6 are block diagrams showing the configuration of the recording side and reproduction side, respectively, in the first practical example of the present invention, and FIG. 4 is a schematic diagram showing the configuration of an example. FIG. 5 is a timing chart for explaining the recording track in detail in the same case, and FIGS. 7 and 8 are the recording side and playback side, respectively, in the second embodiment of the present invention. FIG. 9 and FIG. 12 are block diagrams showing the configuration of the recording side and reproduction side, respectively, in the third embodiment of the present invention, and FIG. 10 is for explaining the operation of the third embodiment. The timing chart of FIG. 11 is a diagram for explaining the same example.

Claims (1)

[Claims] In a magnetic recording/reproduction method in which recording tracks are arranged in parallel in the width direction of the recording tracks and recording is performed, 2's signals with different frequencies are alternately transmitted between two adjacent tracks. Different azimuth angles are used for recording, recording is performed using two different azimuth angles, and during playback, the above azimuth angles are used to distinguish between the track and track being played back and the adjacent tracks on both sides having different frequencies. 20
! A magnetic recording and reproducing system characterized in that tracking deviation is detected from the relative level relationship of these signals and tracking/king control is performed.